A day in coastal California’s micro-climates

It was 101 degrees in Calistoga yesterday when I left, around 4:30 p.m. By the time I reached St. Helena it was down to 94. Then 87 in Napa city. As I crossed the Benicia bridge, across the Carquinez Straights on the 101 freeway heading back to Oakland, I could see, there in the distance, a huge, glowering wall of dark gray hovering on the horizon. At first it looked like the smoke from a forest fire; but it wasn’t, it was the coastal fog.

Bigger and more looming it grew as I drove south. In Richmond, I entered the maelstrom. The blue sky, the picturesque distance disappeared into the gloom; Mount Tam, to the west, vanished as completely as if it had been wiped off the face of the world. The temperature dropped until it was 65 degrees: nearly 40 degrees lower than when I’d left Calistoga, just 1-1/2 hours before. The fog hung low through Albany and north Berkeley, then evaporated as I got to Oakland, where it was again sunny, and the temperature had gone back up to the mid-70s. This was as beautiful, as classic an illustration of Cailfornia’s summer coastal climate as you could possibly wish for. It’s why northern Calistoga specializes in Cabernet Sauvignon (good Charbono, too), why Carneros is good for Pinot Noir, and why the near East Bay is too cold for any serious grapegrowing.

I’d been in Calistoga for a visit and tasting (of various Pinot Noirs) at Atalon, which is part of Jackson Family Wines’ portfolio. It’s on Tubbs Lane; nearby are Summers, Chateau Montelena, Tamber Bey and others. This is the warmest part of Napa Valley, its northwestern-most pocket, where the cooling influence from the Bay pretty much fizzles out. Bo Barrett once told me that there’s something he calls “the Calistoga Gap”—no, not part of the clothing store chain, but a low place in the Mayacamas through which, he said, cooler air from the Russian River Valley funnels in, moderating the temperatures. This may be so; to get to Calistoga from the Russian River Valley (as I’d done that day), you drive east up Mark West Springs Road as it roller-coasters over the mountains, twisting and turning its way towards Highway 128/29. But it’s not clear to me that the Russian River Valley air can actually find its way “over the hill”, to any meaningful extent. Maybe one of my smart readers can explain this. (I had Gus beside me, in the passenger seat, and for a while he seemed like he might throw up, because his little tummy doesn’t do well on twisting mountain roads. But he didn’t.)

The Tubbs Lane part of Calistoga is a distinctive place. To my eye, it’s a bowl of sorts: not like Napa Valley further south, in, say, Oakville or Rutherford, where you have the mountains (Mayacamas and Vacas) neatly lining the western and eastern sides, with the valley broad and expansive inbetween, like the sheet on a bed. Along Tubbs Lane there seem to be mountains everywhere except to the south; it is thus more of an amphitheater. Mount St. Helena looms immediately to the east: this picture, taken at Atalon, only hints at its majestic presence.

On the other side of the mountain, of course, is Lake County.

That 101 temperature yesterday in Calistoga shows how we’re in the midst of a long, severe heat wave here in California. That’s on top of the drought. The state has had some forest fires, but mainly in the Sierra Foothills and around Yosemite; the coast has largely been spared—so far. Everybody’s hoping it will continue to be. The heat is expected today—as I write these words—to be even worse than yesterday, not good news for anyone, including the grapevines that are so close to being harvested in record-early time.

Although it’s only August 1, I haven’t heard that growers are particularly worried. In fact, the scoop is that it will be another fine harvest, coming after 2012 and 2013. Lest anyone think vintage doesn’t matter in California, the evidence proves otherwise. At the Pinot Noir tasting at Atalon, which we did blind, we tasted through multiple Anderson Valley and Russian River Valley wineries, in two flights: the 2011 and 2012 vintages. There was no comparison. The 2011 flight contained some good wines but overall was disappointing. The 2012s by contrast were fat, lush, opulent. There wasn’t a single loser among them.

Since excessive and prolonged heat can impair photosynthesis by causing plants to close their stomata and shut down the photosynthetic process — and irrigating after a heat wave is a common practice — how does California’s drought (and water rationing) limit your response?

And on the subject of climate change affecting future wine grape growing areas, see these articles: